Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations only cover the safety profile (non-read-only, non-idempotent, non-destructive, closed-world), and the description adds genuinely new behavior: link expiry (1 hour, one-time use), plan-based size ceilings, the fact that a Pro file_id replacement preserves the existing link, and that folder paths are auto-created. Return values are only implied (upload_url, page_url appear inside instructions) rather than stated, which keeps it off a 5.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Every sentence carries operational content — fallback paths, size thresholds, curl syntax, plan gating — and the core fact (one-time, 1-hour link) lands early. It is dense and reads like a runbook rather than being front-loaded with the primary outcome, but there is little dead weight.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description must carry the response shape, and it does so implicitly by referencing upload_url and page_url as things the agent will hand out or use. Combined with the fallback flows and plan limits, an agent can act correctly; an explicit statement of the returned fields would make it complete.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so all three parameters are already documented, including the Pro-only nature of folder and file_id and the link-preserving replace semantics. The description largely restates the file_id behavior rather than adding new syntax or edge-case meaning, so the baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description names the concrete artifact it produces ('Creates a one-time upload link valid 1 hour') and scopes it to files that already exist with explicit size limits. The opening framing ('Preferred way to publish a file that already exists') is slightly off-key for a tool that only mints a link, but the verb+resource are unambiguous once past the first clause.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It gives an explicit decision tree: try a direct HTTP PUT to upload_url first, fall back to upload_file for files under ~100 KB, and for larger files hand the user page_url or the network-settings advice. It also carves out the Pro-only replace path via file_id. This is exactly the when-to-use vs. sibling-alternative guidance an agent needs.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.